Interpretive Summary: Environmental drivers are factors of our immediate and distant surroundings that cause measurable changes in properties of biological communities. Drivers affecting rangeland ecosystems can be divided into physical, social, and economic/policy. Examples of physical drivers are factors such as variability in rainfall and available soil nitrogen and management factors such as livestock grazing practices and prescribed burning. Examples of economic/ policy drivers are domestic and global actions such as tax laws, environmental policies, and trade agreements. Examples of social drivers are trends such as attitudes regarding property rights, prevailing public values about land management, and changes in land occupation. While there is ample evidence that changes in ecosystem properties can be linked to environmental drivers, it is difficult to identify the impact of specific drivers on specific properties at specific times. Although there have been notable improvements in monitoring systems to integrate improved understanding of a wider range of indicators, the problem of linking generic attributes to site-specific decisions remains. Incorporation and refinement of our understanding and monitoring effects and interactions of different drivers will contribute to improvements in these predictive capacities. A spectrum of environmental drivers has typically not been explicitly incorporated into monitoring schemes. Yet, analysis of major changes in rangeland ecosystem function in both the distant and immediate past clearly demonstrates that even a less-than-complete understanding of environmental drivers and incorporation of that information into decision-making could dramatically improve outcomes and lead to enhanced sustainability.

Technical Abstract:
Environmental drivers are factors that cause measurable changes in properties of biological communities. Examples of drivers can include environmental factors, such as rainfall variability and available soil nitrogen; management factors, such as livestock grazing practices and prescribed burning; government factors, such as tax laws and environmental policies; and societal factors, such as attitudes regarding property rights and public values. It is difficult to identify the impact of specific drivers on specific properties at specific times since drivers seldom operate independently, at similar scales, or in isolation from other drivers. Impacts of some drivers, especially nonecological, may not be quantifiable. Yet, any interest in understanding how systems will respond to specific drivers, such as grazing management practices, requires monitoring of system dynamics and pertinent environmental drivers at appropriate scales. For example, risk assessments, adaptive management analyses, or management by hypothesis require understanding linkages between environmental drivers and various management options on ecological properties of managed systems. Any type of predictive management strategy for proposing future options would require an understanding of biological responses to environmental stressors. Though our abilities to generate accurate predictions are currently limited, conceptual models of system response to drivers are improving. Continued incorporation and refinement of understanding and monitoring effects and interactions of different drivers will contribute to improvements in these predictive capacities. It is important to remember we are developing monitoring systems for the future, as well as for today.